Studies of Antibody Diversity and Genome Stability: Regulation of Activation-Indu

描述（由申请人提供）：激活诱导脱氨酶（AID）是一种使脊椎动物抗体基因突变的酶。这些艾滋病介导的突变对于生物体产生识别和根除多种微生物感染的特异性抗体是必要的。然而，如果AID没有得到适当的调节，它可以改变对正常细胞功能重要的基因的DNA序列并导致疾病。事实上，一些淋巴瘤和白血病是由AID的异常活动引起的。为什么AID只能改变抗体基因的DNA序列，而不能改变其他基因的DNA序列，人们对此知之甚少。最近，catenin 2 like 1蛋白（CTNNBL1）被发现与AID发生物理相互作用。目前对CTNNBL1的生理功能知之甚少。然而，AID需要与CTNNBL1相互作用才能特异性地改变抗体基因中的DNA序列。在这项研究中，将结合高通量方法，包括下一代测序和微阵列分析，以及靶向生化和免疫学分析，来研究AID如何特异性地突变抗体基因，特别是在CTNNBL1存在和不存在的情况下，AID可进入的基因组区域。这些实验还将检测由于CTNNBL1缺失而引起的转录和剪接的任何改变，从而揭示CTNNBL1的正常细胞功能。将通过质谱分析、诱变分析和免疫学实验来确定AID与CTNNBL1相互作用的分子细节，并阐明CTNNBL1调控AID靶向活性的机制。预计这项研究的结果将对理解抗体多样性产生的机制以及创造新的治疗策略以最大限度地减少基因组疾病和癌症具有重要意义。

DESCRIPTION (provided by applicant): Activation-induced deaminase (AID) is an enzyme that mutates genes for antibodies in vertebrates. These AID-mediated mutations are necessary for an organism to generate specific antibodies to recognize and eradicate great varieties of microbial infections. However, if AID is not properly regulated, it can change DNA sequences of genes important for normal cell functions and cause diseases. Indeed, some lymphomas and leukemias are caused by abnormal activities of AID. How AID can change DNA sequences only in antibody genes but not in other genes is poorly understood. Recently, the catenin 2 like 1 protein (CTNNBL1) has been found to physically interact with AID. Little is known for the physiologic function of CTNNBL1. However, the interaction with CTNNBL1 is required for AID to change DNA sequences specifically in the antibody genes. In this study, a combination of high throughput approaches including next-generation sequencing and microarray analyses and targeted biochemical and immunologic analyses will be used to investigate how AID specifically mutate antibody genes, particularly what genomic regions are accessible to AID, both in the presence and in the absence of CTNNBL1. These experiments will also detect any alterations in transcription and splicing caused by the absence of CTNNBL1, and thereby shed lights on normal cellular functions of CTNNBL1. Mass spectrometry, mutagenic analyses and immunologic experiments will be performed to determine the molecular details of the interaction between AID and CTNNBL1 as well as to elucidate the mechanisms by which CTNNBL1 regulates the targeted activity of AID. It is anticipated that results from this study will be highly relevant for understanding the mechanisms underlying the generation of antibody diversity, and in the creation of new therapeutic strategies to minimize genomic disorders and cancers. PUBLIC HEALTH RELEVANCE: AID (activation-induced deaminase) is the DNA mutating enzyme responsible for changes of the antibody genes to generate different antibodies, but untimely or accidental actions of AID on cellular genes can cause cancers, immune-mediated or genetic diseases. The goal of this fellowship is to find out how AID is finely controlled to introduce mutations on genes for antibodies against microbes but not undesirable and harmful changes on genes of regular functions. Knowledge gained from this study will help understanding normal immune functions and facilitate the creation of new therapeutic strategies to minimize diseases such as cancers.